1. Field of the Invention
This invention relates, generally, to hip surgery. More particularly, it relates to a surgical technique for hemiarthroplasty that is minimally invasive and has reduced post-operative pain.
2. Description of the Prior Art
Approximately 300,000 patients experience a fracture of the hip due to osteoporosis every year. These patients are generally elderly and often have multiple pre-existing medical conditions, making them poor candidates for a surgical procedure.
Current treatments for hip fracture include total hip arthroplasty (replacement of the femoral and acetabular sides of the hip joint), hip hemiarthroplasty (replacement of the fractured femoral side of the hip only, leaving the native acetabulum in place), and hip pinning with cannulated screws. Occasionally a hip fracture will warrant a hip disarticulation.
The type of treatment for hip fracture is decided by factors such as the patient's pre-fracture level of activity, the existence of pre-existing arthritis, and the patient's health and ability to tolerate surgery. Younger patients who are active are often candidates for hip pinning, so that their native femur may be saved. For patients who are ambulatory and have arthritis, total hip arthroplasty is typically performed. For patients who are ambulatory and do not have arthritis, hip hemiarthroplasty is typically performed. Though less common, hip pinning may be chosen for elderly patients who are not ambulatory if they are judged to be poor surgical candidates and require a less invasive procedure.
International Patent Application No. PCT/US99/08906 discloses a surgical technique of removing the fractured femoral head from a body and inserting a neo-femoral head joined to the native femoral neck. The neo-femoral head comprises a bio-absorbable expandable balloon that is filled with a molding material within the body and forms the shape of the neo-femoral head.
However, several issues arise in this conventional technology. First, the device is made of a bio-absorbable material that will disintegrate over time. The intent of the procedure is for the patient to undergo 6-8 weeks of post-operative crutch-walking, during which time bone will replace the inserted material. Based on known rates of creeping substitution, the process by which bone incorporates bone-line materials may take 10-20 years, prior to which the device would likely fail. Moreover, the neo-femoral head is supported only by a thin cylindrical stem through the femoral neck, thus being susceptible to cantilever bending forces.
Accordingly, what is needed is a rigid, minimally invasive, immediately weight-bearing surgical procedure and apparatus for performing hip hemiarthroplasty. However, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill how the art could be advanced.
While certain aspects of conventional technologies have been discussed to facilitate disclosure of the invention, Applicants in no way disclaim these technical aspects, and it is contemplated that the claimed invention may encompass one or more of the conventional technical aspects discussed herein.
The present invention may address one or more of the problems and deficiencies of the prior art discussed above. However, it is contemplated that the invention may prove useful in addressing other problems and deficiencies in a number of technical areas. Therefore, the claimed invention should not necessarily be construed as limited to addressing any of the particular problems or deficiencies discussed herein.
In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.